Mailbox alert flag



FIG. 1 is a perspective view of a mailbox alert flag, as shown on an existing mailbox and in a deployed state;

FIG. 2 is an enlarged top plan view thereof;

FIG. 3 is an enlarged bottom plan view thereof;

FIG. 4 is an enlarged front view thereof;

FIG. 5 is an enlarged rear view thereof;

FIG. 6 is an enlarged side view thereof; and,

FIG. 7 is a perspective view of a mailbox flag, as shown mounted on an existing mailbox and in a resting state.

The broken line showing of a mailbox and post is included for the purpose of illustrating environmental structure and forms no part of the claimed design. 

The ornamental design for a mailbox alert flag, as shown and described. 